脉冲电压下尼龙的激光触发沿面闪络特性

Laser-triggered Flashover Characteristics of Nylon in the Air Condition with Pulsed Voltage

为研究脉冲电压下的激光触发沿面闪络特性,在试验系统中建立了精确的激光触发沿面闪络试验系统,解决了激光脉冲与试品上所加脉冲电压的同步问题,在此基础上应用平板电极和柱状尼龙绝缘材料进行了激光触发沿面闪络试验。试验中采用60 mm直径的铜材料平板电极,试品为20 mm直径、6、8、10 mm厚的尼龙材料圆柱绝缘材料,试验中激光波长为10645、32 nm并聚焦成2 mm×30 mm的长方形光斑,得到在不同的激光能量密度及施加电压下的闪络时延和抖动时间,并探讨了激光触发沿面闪络的机理。研究表明:激光能量密度越大、施加电压越高,闪络时延和抖动时间越小。

To study the characteristics of laser-triggered surface flashover in voltage pulse, the synchronization problem of laser pulse and voltage pulse was solved through establishing a high precision laser trigger system and using a self-made digital delay/pulse generator. A single/double harmonic, with wavelength 2 of 1064/532 nm, Q-switched Nd：YAG laser is used to trigger the surface flashover. Based on the results of the delay time and the timing sequence of the laser triggering system, the Marx＇s trigger and Xe lamp of laser were controlled by digital delay/pulse generator, then the Q-switch of laser was controlled by output of Marx generator, the synchronization of laser pulse and voltage pulse was obtained through adjusting the channel delay time of digital delay/pulse generator. In addition, experiment of laser-triggered surface flashover was carried out using the flat electrodes and columned insulators of nylon based on the test system. Electrode was copper electrode with 60mm diameter. Test sample was nylon sample with 20 mm diameter, the test sample＇s thickness were 6 mm, 8 mm and 10 mm, the pulse＇s wavelengths were 532 nm and 1064 nm, and the laser was focused with 2 mm×30 mm rectangle. Accordingly, the flashover delay time and jitter time were obtained through experiment, and possible mechanism of laser-triggered flashover was brought foreword. The results show that flashoven delay time and jitter time decrease and laser energy density increases with pulsed voltage.